> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://docs.clientexec.com/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Blank Screen During Upgrade/Installation

If you are getting a blank screen when installing Clientexec or after upgrading or moving to a new host there are a couple of things you can check.

1.  Please have your host check the apache error_log and remove any rules blocking or preventing ClientExec from loading.
2. If you are using Ubuntu and opcache with an old version of PHP 8.1. there is a bug in the earlier PHP version that will randomly causes a white screen, please upgrade to the latest version of php 8.1 and see if that resolves your issue.

If you need any further help you can contact us on live chat or [submit a ticket](https://www.clientexec.com/members/index.php?fuse=support&controller=ticket&view=submitticket).